The invention is broadly concerned with and intended particularly as a control system for cable television transmission lines.
In cable television systems, a line amplifier is set up to compensate for attenuation of signals through coaxial cables. Generally, such line amplifiers have been located several meters above ground (for example, atop telephone poles). Up to this time, to observe and maintain cable television transmission lines, a man must climb a telegraph pole, open a cover of the line amplifier box, loosen screws to bare test points, and collect information about it by directly measuring signal input and output levels, AC voltages and DC voltages. The man must climb a telegraph pole with measurement sets. This method of observation and maintenance is dangerous and it takes a long time. A need exists for a cable television transmission control system which is so constructed as to be safe to work with and to take a short time to observe and control the operating conditions of the line amplifiers.
FIG. 1 illustrates the typical line amplifier 8 in which the actual amplifier 2 is contained within a case 7. The cable 1 is connected to the input of the amplifier 2 via a directional coupler 3 and the output of the amplifier 2 is output from the case 7 via a directional coupler 4. The amplifier is further connected to a power supply 5 and a control circuit 6.
FIG. 2 illustrates the typical physical arrangement of the line amplifier 8 which is atop a telephone pole 9.